Method of and apparatus for facsimile telegraphy



.A. MUNTEILHET.

METHOD 0F AND APPARATUS FOR FACSIMILE TELEGHAPHY. APPLmATloN FILED sEPT.15,191s.

1,434,064. Patented 0t.31,1922. t

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gjm/venan patented @nigh i922.

.ANININ MONTELHET, @E PARS, FRANCE, ASSEGNQ'EL iDEQ TELEGRA'JPHES EDOUARD BEETJE, @T

METED @IF AND ATPARATU@ Application lfiled september l5, i933. Serial Eile. 739,923. (GRANTED UNLEBR. Pllttlll' Ulli THE will @F MARGH 3, will, al STAT. willi.)

To' all whom it 'may concern:

Be it known that il, Airroiiin Mourniniin'r, citizen of the Republic et France, residing in Paris, in the lRepublic of France, have invented certain new and useful Improvements in a Method oit' and Apparatus i'or llacsimileA rlelegraphy, of -which the -iollovving is a speciiication.

, rllhe present invention relates to a method of and .apparatus lor the transmitting and receiving by aid of the existing line or Wireless. telegraphic stations, messages, designs of every kind, cliches, reliefs, photographs, and the like, excepting, however, ordinary signatures.

According to the invention energy impulses are sent out troni the transmitting" station both in the case of Wireless and' line telegraphy which are always of the saine value, that is to say'are always constant in value. The transmittingstation has a local circuit carryin a variable electric current which on reac ing a predetermined value sends out similar energy impulses which are Constantin value, The receiving station is also provided with a local circuit'vvhich is closed on the reception of the constant energy impulse and is closed for a time during which the impulse is sent. The actual receiving apparatus is preferably .of the optical kind.` The local circuitinthe transmitting station only 'cooI crates with the main circuit when' a regu ar periodic variable in the local circuit attains a 'value corresponding to a certain particular value of anadjustable variable in vthe said local circuit. The receiver may be provided vvith a similar periodic` variable driven synchronously with that' in the transmitting circuit in which case the signal received would depend on the time at which-theiinpulse was received for its value as. regards the current, the current var ing lfrom this value to a predetermined xe ,value during the sending of the impulse' each impulse naturally 'lasting for a very s ort time. Y 0r again this 'synchronized periodic variable need not be employed,'the signal receivedA depending entirely-on thetime during which the signal ln the drawing there is dia rammatically ings or thelihe by means of ordinary Wireless transmission.

At the transmitting station there is a local circuit including a battery or source of current S, the apparatus A, for example, as

'disclosed in the prior patent, to Belin,

which the Whole range 'of the variable resistance c is covered by the sliding contact, a point, or more preferably, a very small porti-on of the document is exploredv or placedin 'circuit by means of 'an appropriate con- 'tact in series with the' circuit. During this exploration 'and' consequent upon the natureI of the document and of the member' vvhich translates the values (reliefs by means of a rhe'ostat or microphone, er again directly by means of an insulated selenium cell, or

through a photographic'cliche, etc.)the resistance of the local circuit is varied and av Contact moves over the variable resistance in 1 such manner that at last it Will arrive at a condition When the algebraical sum'of the tWo variations are such that the relay R can be actuated. The emission of a 'Wave takes place at this 'actual moment. `llt'is evident that the faster the resistance operates, the greater can be the speed or degree of nneness ofthe exploration and more frequent Will be the emissions of Waves by the an-t l tenna.

lit the receiving station on the antenna L there is arranged a relay R or like arrangement which, attlie receiving of a Wave by the antenna, closes a local circuit Sp ln this circuit there is included a variable resistance o and the registering or indicating appa-- ratus E, such as a galvanometer or like sensitive member.- The moving Contact of the variable resistance has a similar' movement to that ot the resistance c in the localtransmitting circuit. The two movements are synchronous and may be, as desired, either in the same direction or inA opposite directions so as to produce in their respective cir-A lll@ cuits similar or contrary effectst On a Wave arriving and causing the closing of the local receiving circuit at the momentwhen the resistance c lies at a value similar to that of the resistance c the resistanceA of the local circuit' is varied proportionally to the .re-l sistance introduced into the circuit by the element explored -in the local transmitting 'circuitg' consequently the receiver reproduces or faithfully translates by its own mechanism the image -or the document passed through the transmitter.

Assuming p is the maximum value of the variable resistance c in the local transmitting circuit; and that a is the maximum re-v sistance of the Whole circuit which includes the relay, the maximum value of resistance due to the signal arrangement, and the maximum value p of the variable resistance; and equals the resistance in the circuit at `which the relay R operates, then in order that the relay Will he operated by varying the cursor, it is essential that 0:p is at least equal to m. y

Now if due tothe exploring of a relief (or to-theinsertion of an insulated selenium cell), the maximum resistance of the local circuit is diminished from the value o: by a quantity (naturally p must be greater than the maximum value of the relay Ywill 0pwhen the moving contact of the variable resistance of the transmitting circuit is at the 'The moving contactyo'f the variable resistance of the local receiving circuit Will be-at an identical value p that is to say the local receiving circuit which had a resistance al-p, Will then have a resistance It therefore registers or indicates a variation (where a', and p indicate, in the receiving'circuit, the corresponding proportional values of their respective significations in the transmitting circuit).

In considering the oint which explores the document for obtaining the signals'it is necessary to point out that the Whole of the variable resistance is run off by the cursor in a very short time t of the minute exploration' covered by one signal.' During this time i t the cursor'will reach the point at which the relay operates say at the end of the time d it follows that the signal Will be transmitted during a time (t-dt). Y On the arrival. of the signal the relay at the receiving station is operated at the instant alt and the local` circuit will remain closed during the same 'interval-of time (t-(Zt).` As the variable resistances are operated synchronously the local circuit of the receiver will operate for exactly lthe same time and with the same conditions of current as' are taking place in the local transmitting circuit.

The lsynchronism of thelvarying resistinea-,oca

ances may be assured in any desired manner `The present invention has the characteristic feature of using for radio-telegraphic transmission Waves or emissions of constant degree combined with a local circuit having -a variable resistance at the transmitter and at the receiving stations7 the variations in the one variable resistance 5 being synchronous Withthose of the other the two being equal; proportional, similar, or inverse.

The balancing resista-nceymay, if desired,

be eliminated together yvith the moving con-` tact of the receiving circuit. In this case the scale of tints -Which is employed to record the varyingsignals received, would' `loe-lilsevvise eliminated and replaced by a slotted diaphragm similar to those usedfin portrait photography, which only .allows a full signal or no signal at all to be recorded and not a signal the strength of which varies. As long as the value 'm is not attained in the transmitting circuit, the spot Will remain either outside the slot or on the slot of the diaphragm according to the sense of Athe picture to be obtained. At the moment when the value is attained the spot takes up the contrary positions and -the different tonalities or degrees ofvalue will lresult not so much owing to the greater or less degree of extinction of the luminousrays, but owing to the reater or less duration of theiraction, Whic comes to 'the same thing.

. It is known that the blackening of -a photographic sensitive layer "isproportional not to the quantity of light received but to the logarithm of this quantity of light and this factor should be taken into account in the construction or selection of the balancing resistance 'of the transmitting circuit.

The mode of transmission may evidently. be applied in either of the twoforms of receptvion to line telegraphy, the Wave roducing apparatus and the antennae-L an L being then replaced. by a source of current and the line Wire. i

It has been "found lthat an apparatus of this kind may be very' advantageously used for transmission of :telephotographv over very long distances by a single Wire havingl an earth return'l thus eliminating the energy Wasted in the -line for actuating the receiving apparatus, the arrangement merely requiring ,slight4 detail alterations.

Having now particularly described and ascertained the nature of the said invention and in what manner the same is to be' performed, I declare that What I claim is:

1. In an arrangement for transmitting messages or designs, such as photographs,

clichsand the like, the combination of synv in which the energy impulses are transmitted by wireless telegraphy.

3. n a system for transmittin facsimiles by telegraph, the combination with a transmitting station having a periodically varying resistance in the local circuit thereof, of a receiving station having a vperiodical varying resistance in its local circuit in synchronism With that of the transmitting station, and means energizing the local circuit of the receiving, station to indicate the value of the variable atthe transmitter when la signal impulse of constant value is received by the main circuit substantially as described.

4. In a Wireless transmitter apparatusv for transmitting facsimiles by telegraphy, the combination of means for translating the facsimile into a certain value of resistance in the local circuit @tithe transmitter, a resistance in said circnit variable periodically between certain values,rand a relay in said circuit arranged tojbe energized when the total resistance of the local circuit attains a certain predetermined value after a lapse of time varying according to the signal to be transmitted, thereby causing the transmission of a definite constant signal impulse by the main circuit.

5. In a system for Wireless transmission v of facsimiles, the combination with a transmitting station having a periodically varying resistance in its local circuit, a resistance in said circuit set to a temporary value dependent upon the signal to be transmitted, and means operable upon the attaining ot' a predetermined total value of resistance in,

said local circuit to send a constant signal impulse, of a receivlng station having a local circuit and a relay having contacts in Y'said circuit adapted to close the same and energized by the aerial circuit.

6.- In a system for Wireless transmission of, facsimiles, as claimed in claim 3, combined with a relay at the receiving station which is adapted to close the local circuit upon the reception of a signal impulse of constant value from the main circuit.

7, A system for Wireless transmission of facsimiles embodyin a local circuit, means for producing a regu ar periodic variable in the local circuit, an adjustable variable in said local circuit, and means to' effect the main circuit to cause the transmission of a constant energy impulse when the regular periodic variable in the local circuit attains avalue correspondingto a certain particular value of the adjustable variable in said circuit.

8. A system for wireless transmission of acsimiles as claimed in claim 7, wherein the value of the variable transmitted depends upon the duration of the signal impulse.

In Witness whereof I have hereunto 'signed my name this first day of September, 1913, in the presence of two subscribing witnesses.

ANTONIN MONTEILHET. 

